Werndl C. (2012) Observational Equivalence of Deterministic and Indeterministic Descriptions and the Role of Different Observations. In: de Regt H., Hartmann S., Okasha S. (eds) EPSA Philosophy of Science: Amsterdam 2009. The European Philosophy of Science Association Proceedings, vol 1. Springer, Dordrecht
Recently some results have been presented which show that certain kinds of deterministic descriptions and indeterministic descriptions are observationally equivalent (Werndl 2009a, 2011). These results prompt interesting philosophical questions, such as what exactly they show or whether the deterministic or indeterministic description is preferable. There is hardly any philosophical discussion about these questions, and this paper contributes to filling this gap. More specifically, first, I discuss the philosophical comments made by mathematicians about observational equivalence, in particular Ornstein and Weiss (1991). Their comments are vague, and I argue that, according to a reasonable interpretation, they are misguided. Second, the results on observational equivalence raise the question of whether the deterministic or indeterministic description is preferable relative to evidence. If the deterministic and indeterministic description are equally well supported by evidence, there is underdetermination. I criticise Winnie’s (1998) argument that, by appealing to different observations, one finds that the deterministic description is preferable. In particular, I clarify a confusion in this argument. Furthermore, I show that the argument delivers the desired conclusion relative to in principle possible observations, but that the argument fails relative to currently possible observations.